[ltt-dev] Trace "destroy" hangs, lttd keeps running

[Mathieu Desnoyers]

* Ashwin Tanugula (ashwin.tanugula at broadcom.com) wrote:
> 
> > >
> > > I continued my testing using "return 1;" to reproduce the errors with 
> > > the viewer, so that I can send you my trace data.
> > >
> 
> > OK. Then let's revert to the previous lttng assumption: synchronized TSCs across MIPS cores. Does that work for you ? (I see that you configured your kernel with support for 2 CPUs. Do you have an SMP board ?)
> 
> Yes, I am running the kernel ins SMP mode.
> 
> In UP mode I don't see the UNSYNCHRONIZED TSC problem (which I guess
> is obvious)
> 

Hi Ashwin,

Then you'll have to try disabling everything that can try to scale the
CPU frequency when you boot your system, and see if it works better.

Support non-synchronized TSCs on MIPS will have to wait until

a) This feature gets requested as a contract.
b) I can get my hands on a SMP mips32 board with such frequency scaling.

So for now let's focus on just making sure LTTng works when all
frequency scaling features are disabled at boot time.

Thanks,

Mathieu



> Thanks,
> Ashwin
> 
> > MIPS assume synchronized TSC
> 
> > Code for non-synchronized TSC support was broken (at least for MIPS32). I suspect the spinlock did not do well with NMIs or something like this. Revert to assuming synchronized TSCs across cores until someone send me a MIPS board to play with.
> 
> 
> 

-- 
Mathieu Desnoyers
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